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Periaxonal Application of Capsaicin as a Novel Method for Selective Afferent Renal Denervation
Author(s) -
Foss Jason,
Engeland William C,
Osborn John W
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.lb838
Subject(s) - calcitonin gene related peptide , denervation , endocrinology , medicine , efferent , capsaicin , kidney , calcitonin , chemistry , afferent , neuropeptide , receptor
Because the differential role of afferent and efferent renal nerves in hypertension is unclear, we developed a method of afferent renal denervation (ARDN) by periaxonal application of capsaicin (renal‐CAP). Sprague‐Dawley (SD) rats were subjected to SHAM surgery or renal‐CAP and sacrificed after 10 days. Immunohistochemistry (IHC) staining for calcitonin gene related peptide (CGRP; a marker of afferent fibers) and tyrosine hydroxylase (TH; a marker of efferent fibers) showed near complete depletion of CGRP from the kidneys with no effect on TH. We next tested the hypothesis that afferent renal nerves regulate arterial pressure (AP) and fluid balance during chronic salt loading. SD rats were subjected to SHAM surgery or renal‐CAP, instrumented with telemeters for measurement of AP and heart rate (HR), and placed in metabolic cages. Rats were fed a 0.1% NaCl diet for 2 weeks, 4% NaCl for 3 weeks and 8% NaCl for 2 weeks. There were no differences in AP or sodium/water balance between SHAM and renal‐CAP rats throughout the protocol; however, SHAM rats exhibited progressive bradycardia that was attenuated in renal‐CAP rats (p<0.05). IHC showed partial depletion of CGRP after 7 weeks. We conclude that renal‐CAP is an effective method of ARDN, afferent renal nerves play a minimal role in the regulation of AP and fluid balance in normotensive rats, and afferent renal nerves mediate sodium dependent decreases in HR.